Field of the Invention
The present invention relates generally to power trowels for finishing concrete surfaces such as floors, more specifically to self-propelled ride-on trowels, and most specifically to a hybrid drive train for a self-propelled ride-on trowel having dual counter-rotating rotors.
Description of Related Art
Self-propelled riding trowels, in general, are well known in the art. Primarily these trowels are used in concrete finishing operations typically on large-scale pours for floors and foundations to allow an operator to finish vast areas of concrete quickly and efficiently. An on-board engine typically serves as the prime mover for the riding trowel. Other components of the drive train, typically a combination of hydraulic and mechanical linkage, couple the mechanical energy of the engine to two counter-rotating rotor assemblies at the base of the trowel. The rotor assemblies drive metal trowel blades that provide both the motive force for moving the trowel and also the means for finishing the concrete surface beneath the trowel.
The larger class of self-propelled riding trowels use 70 hp or larger size engines, weigh in excess of 2300 lbs, and typically have output torque ratings in the 1000 ft-lb to 1500 ft-lb range. While high torque ratings are desirable when driving the rotor blades under the weight of the trowel against a concrete pour, higher-powered engines generally increase fuel consumption and lower overall efficiency. What is needed to advance the design of riding trowels is a drive train that can deliver greater torque while maintaining or improving overall efficiency.